Growth and differentiation of craniofacial tissue is complex and involves multiple cell types interacting with each other and a number of hormones and growth factors. Of particular interest are steroids such as glucocorticoids, steroidal alkaloids such as jervine and epidermal growth factor (EGF). These agents are teratogenic at high doses whereas physiological levels of EGF and glucocorticoids are required for normal growth and differentiation.